Leonurine Exerts Anti-Catabolic and Anti-Apoptotic Effects via Nuclear Factor kappa B (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) Signaling Pathways in Chondrocytes

BACKGROUND: Leonurine confers neuroprotection, inhibits myocardial apoptosis, ameliorates endothelial dysfunction, and shows anti-inflammatory effects, and may be beneficial for clinical applications. However, the effects of leonurine on chondrocytes remain unknown. Here, we investigated the protective role of leonurine in rat chondrocytes. MATERIAL/METHODS: To explore the potential therapeutic effect of leonurine against osteoarthritis (OA), rat chondrocytes were treated with IL-1β along with different concentrations of leonurine in vitro. The levels of matrix metalloproteinases (MMPs), ADAMTS, Bax, and Bcl-2 were measured by PCR, ELISA, and Western blotting. Caspase-3 activity in chondrocytes was determined using a caspase-3 activity assay. Western blotting was also performed to examine activation of the NF-κB and mitogen-activated protein kinase (MAPK) pathways to elucidate the likely regulatory mechanisms. RESULTS: Leonurine counteracted IL-1β-induced production of MMP-1, MMP-13, ADAMTS-4, and ADAMTS-5. Leonurine treatment reduced both the mRNA and protein levels of Bax and increased the level of Bcl-2. Leonurine also inhibited the activity of caspase-3 in IL-1β-induced chondrocytes. Furthermore, the activation of MAPK and phosphorylation of p65 were suppressed by leonurine. CONCLUSIONS: The results of this study indicate that leonurine exerts anti-catabolic and anti-apoptotic effects in chondrocytes in vitro via suppression of the NF-κB and MAPK signaling pathways.